连通容器纳米粉尘爆炸火焰与压力耦合影响机制研究

To specify the anti-explosion geometry and structure design methods and develop the explosion suppression and venting standards and equipment, it is necessary to fully understand the basic phenomenon and dynamic evolution during dust explosion in interconnected vessels. This project aims to study the effects of particle characteristics, vessel geometries and ignition sources on flame accelerations and overpressure behaviors during nano-dust explosion in interconnected vessels through large scale experiments and fluid dynamics, heat transfer and reaction kinetics theory. The dynamic couplings of flame acceleration and pressure piling, pressure oscillation would be revealed. Based on the Eulerian-Lagrangian approach, CFD codes coupling the dynamic relationship between flame acceleration and pressure piling, pressure oscillation, detailed explosion chemical kinetics would be programmed. The present study will provide theoretical and technical support for prevention and mitigation of nano-dust explosions in interconnected vessels.

只有充分地认识连通容器粉尘爆炸的基本现象，掌握爆炸的动力学演化规律，才能对连通容器抗爆几何尺寸及结构设计、爆炸抑制、泄放技术标准制定及装备研发等做出更加准确清晰的指导。因此，本项目通过连通容器纳米粉尘爆炸实验研究与流体、传热、爆炸反应动力学理论分析，研究粉尘特性、容器几何特性及点火源特性对连通容器纳米粉尘爆炸火焰加速传播的影响机理及加速火焰与压力累积、压力振荡的耦合影响规律；基于欧拉-拉格朗日思想，发展耦合火焰加速传播与压力累积、压力振荡相互作用、详细爆炸反应动力学机理的连通容器纳米粉尘爆炸数值计算模型，研究成果可为防控连通容器纳米粉尘爆炸危害提供理论支持与技术支撑。

本项目搭建了连通容器纳米粉尘爆炸试验平台，利用高频动态压力测量技术、高速摄像技术，研究了容器几何特性、纳米粉尘特性及点火源特性对连通容器内爆炸超压与“喷射火”加速传播行为的影响规律，确定了连通容器火焰淬熄的临界条件，揭示了连通容器火焰加速传播与爆炸超压的耦合作用机理，发展了耦合详细反应机理的连通容器纳米粉尘爆炸三维数值计算模型。结果表明：点火后初期阶段，在Landau–Darrieus和Kelvin–Helmholtz不稳定性的作用下燃烧速度增加，主爆容器内爆炸超压达到第一个峰值，管内喷射火焰引燃传爆容器内可燃粉尘，介质与压力回传导致主爆容器内压力达到最大值，由于压力波在主爆容器与传爆容器内的反射，爆炸超压曲线呈现出Helmholtz振荡趋势。连通管道的管径（截面）特性对连通容器“压力累积效应”影响显著，管径越大，爆炸峰值降低、Helmholtz振荡幅度增大。连通管道长度增加对压力峰值与振荡频率影响较小，但增大了火焰传播阻滞效应，更易淬熄。粉尘粒径的改变会改变其热解速率与燃烧模式，导致压力峰值与Helmholtz振荡幅度的改变。发展的耦合详细反应动力学机理的三维数值计算模型可成功再现连通容器粉尘爆炸火焰传播行为和爆炸超压特性。研究成果可为防控连通容器粉尘爆炸提供理论支持和技术支撑。